Undercutter



April 15, 1941. E. s. STRANG UNDERCUTTER Filed Sept. 9. 1939 I N YE N TOR. Iguana .5. 5 TR/m'a.

ATTORNEY.

Patented Apr. 15, 1941 E-Nr OFFICE I v nnnsncor'mn iEdwardS Strang, Longlieach, Cal if. Application September 9, 1839,1Srifll-NOQ 294,119 scam (o1. 255-76 This invention relates to an undercutter, par ticularly applicablefor use in wells, a portion of the well bore having casing therein.

'The purpose of my {invention is to providea novel undercuttnwh'ich can be run into a bored hole-through the casing, and when moved out of 'the'caSingQthe arms of the undercutter are sprungputwardly to iinder'cut the bore-f of the well in a' rap'idandfeffectivemanner. Anobject offmy invention is to provide anovel undercutter in T which the 1 arms, upon each "of whichacutter is mounted, are forced outwardly into undercutting position by means of a'rubber block, which bearsagainst the arm.

Another object is to provide a novel undercutter of the character stated, in which the extensible arms are so mounted in the body as to be effectively supported while carrying the strain of the cutting operation, and further to provide a novel means of a circulating mud around the cutters.

A feature of my invention is to provide a novel antifriction roller or bearing, which bears against the casing While the tool is being well.

Other objects, advantages and. features of invention may appear from the accompanying drawing, the subjoined detailed description, and the appended claims.

In the drawing the single figure is a transverse, sectional view of my undercutter, parts of the undercutter being left in elevation.

Referring more particularly to the drawing, my undercutter comprises a body I, from the upper end of which a threaded pin 2 extends to receive the drill pipe 3. A pin or other suitable threaded coupling 4 depends from the body I, and a pilot bit 5 screws onto the pin or coupling 4. The body I is provided with a plurality of recesses 6. Each of these recesses is adapted to receive a cutting arm 1. Each of the cutting arms I is journaled on a pin 8, which is seated in the body I. An arcuate seat 9 is provided in the body I, and the upper end of each of the arms 1 is curved as shown at Ill, so as to fit in the seat 9. Thus, during the strain of the cutting operation, the arms 'l can bear against the seat 9, thus relieving the pin 8 of an excessive load. A toothed cone cutter II is mounted adjacent the lowered in the outer end of each of the arms 1 and is rotatably mounted on the arm to enable the cone cutter to rotate and cut into the formation during the operation of the tool;

A ball or roller bearing I2 is mounted in each of the arms 1 and protrudes slightly from the outer'surface of the arm so that when the tool is 'being Ioweredintdth well through the case ing, this roller or ball bearing will bear against the casing, and will reduce the frictional-resistance to the downward movement of the tool; A rubber block I3 is positioned between the inner face'of each arm l and the inner surface of the u This. rubber block when permitted to expand will force thearm fl outwardly to the position shown in the drawingg When the tool fs-being run into the holetlirp'ugh'the j-casing, the arms ,I' are forced war ndx efiub r. b c s 3. a compressed, Abolt l 4 extends through the arm 1 and the rubber block l3, and'is threaded into the recess' 'fi, substantially as shown.

body of the tool I. Thus, the rubber blocks are held in position in the tool.

The head of the bolt l4 fits into a counter-bore IS in the arm 1, thus permitting the arm to swing inwardly or outwardly while the tool is being run into the hole through the casing or while the tool is in cutting position. The head of the bolt also acts as a stop to prevent the arm I from moving outwardly more than a predetermined distance.

A circulation bore l6 extends vertically through the undercutter and circulation holes I! extend from the bore l6 into each of the recesses 6. The holes [1 are preferably directed downwardly at an angle so that the circulating mud, is directed against each of the toothed comb cutters I I. As shown in the drawing, the holes I! are preferably opposite the cutters II when the cutters are in expanded position. The operation of my novel undercutter will be apparent from the previous description.

Having described my invention, I claim:

1. An undercutter comprising a body, said body being adapted and arranged to be mounted on drill pipe, said body having a recess in the side thereof, a cutter arm mounted in said recess, a pin extending through the arm and seated in the body whereby the arm is held in position, a cutter journaled on said arm adjacent the lower end thereof, and a rubber block positioned between said arm and the body of the undercutter, said rubber block urging the arm outwardly, an arcuate seat formed in the body within said recess, said arm being adapted and arranged to bear against said seat.

2. An undercutter comprising a body, said body being adapted and arranged to be mounted on drill pipe, said body having a recess in the side thereof, a cutter arm mounted in said recess, a pin extending through the arm and seated in the body whereby the arm is held in position, a cutter journaled on said arm adjacent the lower end thereof, and a rubber block positioned between said arm and the body of the undercutter, said rubber block urging the arm outwardly, a bolt extending through said rubber block and into the arm, the head of said bolt engaging the arms to limit outward movement thereof.

3. An undercutter comprising a body, said body being adapted and arranged to be mounted on drill pipe, said body having a recess in the side thereof, a cutter arm mounted in said recess, a pin extending through the arm and seated in the body whereby the arm is held in position, a cutter iournaled on said arm adjacent the lower end thereof, and a rubber block positioned between said arm and the body of the undercutter, said rubber block urging the arm outwardly, an' arcuate seat formed in the body within said recess, said arm being adapted and arranged to bear against said seat, a bolt extending through said rubber block and into the arm, the head of said bolt engaging the arms to limit outward movement thereof.

4. An undercutter comprising a body, a plurality of recesses extending into the side of said body, an arm mounted in each of the recesses, a pin extending through each of the arms and mounted in the body, a toothed cutter rotatably mounted on each of the arms adjacent the lower end thereof and on the inside of the arm, a rubber block positioned between the inner face of each of the arms and the body, said rubber blocks urging the arms outwardly into cutting position, and a bolt extending through the arms and rubber block and secured in the body, whereby the rubber blocks are held in position.

5. An undercutter comprising a body, a plurality of recesses extending into the side of said body, an arm mounted in each of the recesses, a pin extending through each of the arms and mounted in the body, a toothed cutter rotatably mounted on each of the arms adjacent the lower end thereof, a rubber block positioned between the inner face of each of the arms and the body, said rubber blocks urging the arms outwardly into cutting position, and a bolt extending through the arms and rubber blocks and secured in the body,

whereby the rubber blocks are held in position, said body having a vertical circulation bore extending into the same and a circulation hole extending from the bore into each of said recesses.

6. An undercutter comprising a body, a plurality of recesses formed in the side of said body, an arm mounted in each of the recesses, a pin extending through each of the arms and mounted in the body, a cutter rotatably mounted on each of the arms adjacent the lower end thereof, said cutter being mounted on the inside of the arms, a rubber block positioned between the inner face of each of the arms and the body, said rubber blocks urging the arms outwardly into cutting position, said body having a vertical circulation bore extending into the same and a circulation hole extending from the bore into each of the recesses, said circulation holes being positioned above the cutters and directing fluid towards the cutters.

EDWARD S. STRANG. 

